1. Field of the Invention
The present invention relates to a clamping device for axially harmonically oscillating components and, in particular, to a tool holder for an ultrasonic annular core bit.
2. Description of the Prior Art
The known solutions for connecting two components are divided roughly in thread connections, cone connections, and clamping connections.
British Publication GB 2016350 discloses use of thread and cone connections for tool holders for axially harmonically oscillating ultrasonic working tools. The connection elements are arranged at respective antinodes of a longitudinally extending stationary wave because at these locations node points of tension are formed and, therefore, only minimal axial tension and/or compression stresses are encountered. With ultrasonic, axially harmonically oscillating components, however, cold welds can be formed in the thread or cone surfaces, and the connection elements can be separated primarily with the use of auxiliary means such as special tools.
German Publication DE 4239373 discloses a connection of two tool parts with cooperating plane surfaces, wherein in a radially inner core region of the first tool part, there is formed a hollow space opened at an end surface with bayonet-shaped, inner conical undercut in which a locking peg of the second tool part with a clamping cone engages. Upon axial tensioning, the radially outer plane surfaces of both tool parts becomes frictionally connected. Upon being subjected to ultrasonic action, such locking pegs loosen automatically.
Accordingly, an object of the present invention is a clamping device for axially harmonically oscillating components and which can be closed and opened without use of any auxiliary means.